AES的C++实现(128位密钥)

//  写了一个AES的C++实现，仅支持128位密钥， 写得匆忙，不够规范，仅供参考。

//    AES.h

#ifndef AES_H_
#define AES_H_

#include <bitset>
#include <utility>

using namespace std;

class AES
{
public:
    typedef unsigned char    byte;
    static const int KEY_SIZE = 16;    //    密钥长度为128位
    static const int N_ROUND = 11;
    byte plainText[16];    //    明文
    byte state[16];    //    当前分组。
    byte cipherKey[16];    //    密钥
    byte roundKey[N_ROUND][16];    //轮密钥
    byte cipherText[16];    //密文
    byte SBox[16][16];    //    S盒
    byte InvSBox[16][16];    //    逆S盒   
    void EncryptionProcess();   
    void DecryptionProcess();
    void Round(const int& round);
    void InvRound(const int& round);
    void FinalRound();
    void InvFinalRound();
    void KeyExpansion();
    void AddRoundKey(const int& round);   
    void SubBytes();   
    void InvSubBytes();
    void ShiftRows();   
    void InvShiftRows();
    void MixColumns();   
    void InvMixColumns();
    void BuildSBox();
    void BuildInvSBox();
    void InitialState(const byte* text);
    void InitialCipherText();   
    void InitialplainText();       
    byte GFMultplyByte(const byte& left, const byte& right);
    const byte* GFMultplyBytesMatrix(const byte* left, const byte* right);
public:   
    AES();   
    const byte* Cipher(const byte* text, const byte* key, const int& keySize);   
    const byte* InvCipher(const byte* text, const byte* key, const int& keySize);
};


void AES::EncryptionProcess()
{    //    加密过程
    InitialState(plainText);
    KeyExpansion();    //    密钥扩展
    AddRoundKey(0);    //    轮密钥加
    for(int i = 1; i < N_ROUND-1; ++i)
    {           
        Round(i);
    }
    FinalRound();
    InitialCipherText();
}

void AES::DecryptionProcess()
{    //    解密过程
    InitialState(cipherText);
    KeyExpansion();
    InvFinalRound();
    for(int i = N_ROUND-2; i > 0 ; --i)
    {           
        InvRound(i);
    }
    AddRoundKey(0);
    InitialplainText();
}

void AES::Round(const int& round)
{    //    正常轮
    SubBytes();
    ShiftRows();
    MixColumns();
    AddRoundKey(round);       
}

void AES::InvRound(const int& round)
{    //    正常轮的逆
    AddRoundKey(round);   
    InvMixColumns();
    InvShiftRows();
    InvSubBytes();           
}

void AES::FinalRound()
{    //    最后轮
    SubBytes();
    ShiftRows();
    AddRoundKey(N_ROUND - 1);
}

void AES::InvFinalRound()
{    //    最后轮的逆
    AddRoundKey(N_ROUND - 1);       
    InvShiftRows();
    InvSubBytes();       
}

void AES::KeyExpansion()
{    //    密钥扩展
    const byte rcon[N_ROUND][4] = {
        {0x00, 0x00, 0x00, 0x00}, 
        {0x01, 0x00, 0x00, 0x00},
        {0x02, 0x00, 0x00, 0x00},
        {0x04, 0x00, 0x00, 0x00},
        {0x08, 0x00, 0x00, 0x00},
        {0x10, 0x00, 0x00, 0x00},
        {0x20, 0x00, 0x00, 0x00},
        {0x40, 0x00, 0x00, 0x00},
        {0x80, 0x00, 0x00, 0x00},
        {0x1b, 0x00, 0x00, 0x00},
        {0x36, 0x00, 0x00, 0x00} };       
        for(int i = 0; i < 16; ++i)
        {
            roundKey[0][i] = cipherKey[i];
        }
        for(int i = 0; i < 4; ++i)
        {    //  roundKey[0][16]为cipherKey的转置矩阵
            for(int j = 0; j < 4; ++j)
            {
                roundKey[0][4*i + j] = cipherKey[4*j + i];
            }
        }
        for(int roundIndex = 1; roundIndex < N_ROUND; ++roundIndex)
        {
            byte rotWord[4] = {0x00};
            rotWord[0] = roundKey[roundIndex - 1][3];
            rotWord[1] = roundKey[roundIndex - 1][7];
            rotWord[2] = roundKey[roundIndex - 1][11];
            rotWord[3] = roundKey[roundIndex - 1][15];
            std::swap<byte>(rotWord[0], rotWord[1]);
            std::swap<byte>(rotWord[1], rotWord[2]);
            std::swap<byte>(rotWord[2], rotWord[3]);       
            for(int i = 0; i < 4; ++i)
            {
                rotWord[i] = SBox[ rotWord[i] >> 4][ rotWord[i] & 0x0f ];
                roundKey[roundIndex][4*i] = roundKey[roundIndex - 1][4*i] ^ rotWord[i] ^ rcon[roundIndex][i];
            }
            for(int j = 1; j < 4; ++j)
            {
                for(int i = 0; i < 4; ++i)
                {
                    roundKey[roundIndex][4*i + j] = roundKey[roundIndex - 1][4*i + j] ^ roundKey[roundIndex][4*i + j - 1];
                }
            }
        }
}

void AES::AddRoundKey(const int& round)
{    //    轮密钥加
    for(int i = 0; i < 16; ++i)
    {    //    利用当前分组state和第round组扩展密钥进行按位异或
        state[i] ^= roundKey[round][i];
    }
}

void AES::SubBytes()
{    //    字节代换
    for(int i = 0; i < 16; ++i)
    {
        state[i] = SBox[ state[i] >> 4][ state[i] & 0x0f ];
    }
}

void AES::InvSubBytes()
{    //    逆字节代换
    for(int i = 0; i < 16; ++i)
    {
        state[i] = InvSBox[ state[i] >> 4][ state[i] & 0x0f ];
    }
}

void AES::ShiftRows()
{    //    行变换
    //state第一行保持不变
    // Do nothing.
    //state第二行循环左移一个字节
    std::swap<byte>(state[4], state[5]);
    std::swap<byte>(state[5], state[6]);
    std::swap<byte>(state[6], state[7]);       
    //state第三行循环左移两个字节
    std::swap<byte>(state[8], state[10]);
    std::swap<byte>(state[9], state[11]);
    //state第三行循环左移三个字节
    std::swap<byte>(state[14], state[15]);
    std::swap<byte>(state[13], state[14]);
    std::swap<byte>(state[12], state[13]);   
}

void AES::InvShiftRows()
{    //    行变换反演
    //state第一行保持不变
    // Do nothing.
    //state第二行循环右移一个字节
    std::swap<byte>(state[6], state[7]);
    std::swap<byte>(state[5], state[6]);
    std::swap<byte>(state[4], state[5]);       
    //state第三行循环右移两个字节
    std::swap<byte>(state[9], state[11]);
    std::swap<byte>(state[8], state[10]);
    //state第三行循环右移三个字节
    std::swap<byte>(state[12], state[13]);
    std::swap<byte>(state[13], state[14]);       
    std::swap<byte>(state[14], state[15]);   
}

void AES::MixColumns()
{    //    列混淆
    byte matrix[4][4] = {
        {0x02, 0x03, 0x01, 0x01},
        {0x01, 0x02, 0x03, 0x01},
        {0x01, 0x01, 0x02, 0x03},
        {0x03, 0x01, 0x01, 0x02}};
        const byte* temp = GFMultplyBytesMatrix((byte*)matrix, state);
        for(int i = 0; i < 16; ++i)
        {
            state[i] = temp[i];
        }
        delete[] temp;
}

void AES::InvMixColumns()
{    //    列混淆反演
    byte matrix[4][4] = {
        {0x0e, 0x0b, 0x0d, 0x09},
        {0x09, 0x0e, 0x0b, 0x0d},
        {0x0d, 0x09, 0x0e, 0x0b},
        {0x0b, 0x0d, 0x09, 0x0e} };
        const byte* temp = GFMultplyBytesMatrix((byte*)matrix, state);
        for(int i = 0; i < 16; ++i)
        {
            state[i] = temp[i];
        }
        delete[] temp;
}

void AES::BuildSBox()
{    //    构建S盒
    byte box[16][16] =
    {
        /*        0     1     2     3     4     5     6     7     8     9     a     b     c     d     e     f */
        /*0*/  {0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76},
        /*1*/  {0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0},
        /*2*/  {0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15},
        /*3*/  {0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75},
        /*4*/  {0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84},
        /*5*/  {0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf},
        /*6*/  {0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8},
        /*7*/  {0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2},
        /*8*/  {0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73},
        /*9*/  {0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb},
        /*a*/  {0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79},
        /*b*/  {0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08},
        /*c*/  {0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a},
        /*d*/  {0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e},
        /*e*/  {0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf},
        /*f*/  {0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16}
    };
    for(int i = 0; i < 16; ++i)
    {
        for(int j = 0; j < 16; ++j)
        {
            SBox[i][j] = box[i][j];
        }
    }
}

void AES::BuildInvSBox()
{    //    构建逆S盒
    byte box[16][16] =
    {
        /*        0     1     2     3     4     5     6     7     8     9     a     b     c     d     e     f */
        /*0*/  {0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb},
        /*1*/  {0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb},
        /*2*/  {0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e},
        /*3*/  {0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25},
        /*4*/  {0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92},
        /*5*/  {0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84},
        /*6*/  {0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06},
        /*7*/  {0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b},
        /*8*/  {0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73},
        /*9*/  {0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e},
        /*a*/  {0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b},
        /*b*/  {0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4},
        /*c*/  {0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f},
        /*d*/  {0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef},
        /*e*/  {0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61},
        /*f*/  {0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d}
    };
    for(int i = 0; i < 16; ++i)
    {
        for(int j = 0; j < 16; ++j)
        {
            InvSBox[i][j] = box[i][j];
        }
    }
}

void AES::InitialState(const byte* text)
{    //    state初始时候为明(密)文矩阵的转置矩阵
    for(int i = 0; i < 4; ++i)
    {    //转置text存放在state中
        for(int j = 0; j < 4; ++j)
        {
            state[4*i + j] = text[4*j + i];
        }
    }
}

void AES::InitialCipherText()
{    //    state被复制到输出矩阵中   
    for(int i = 0; i < 4; ++i)
    {    //转置state存放在cipherText中
        for(int j = 0; j < 4; ++j)
        {
            cipherText[4*i + j] = state[4*j + i];
        }
    }
}

void AES::InitialplainText()
{    //    state被复制到输入矩阵中
    for(int i = 0; i < 4; ++i)
    {    //转置state存放在plainText中
        for(int j = 0; j < 4; ++j)
        {
            plainText[4*i + j] = state[4*j + i];
        }
    }
}

AES::byte AES::GFMultplyByte(const byte& left, const byte& right)
{    //有限域GF(2^8)上的乘法
    byte temp[8];
    bitset<8> bits((unsigned long)right);    //把right化为8个二进制位存放在bits中
    temp[0] = left;
    for(int i = 1; i < 8; ++i)
    {
        if(temp[i-1] >= 0x80)    //若 (temp[i-1] 首位为"1"
        {
            temp[i] = temp[i-1] << 1;
            temp[i] = temp[i] ^ 0x1b;    //与(00011011)异或
        }
        else
        {
            temp[i] = temp[i-1] << 1;
        }
    }
    byte result = 0x00;
    for(int i = 0; i < 8; ++i)
    {
        if(bits[i] == 1)
        {
            result ^= temp[i];
        }
    }
    return result;
}

const AES::byte* AES::GFMultplyBytesMatrix(const byte* left, const byte* right)
{    //有限域GF(2^8)上的矩阵(4*4)乘法
    AES::byte* result = new AES::byte[16];
    for(int i = 0; i < 4; ++i)
    {
        for(int j = 0; j < 4; ++j)
        {
            result[4*i + j] = GFMultplyByte(left[4*i], right[j]);
            for(int k = 1; k < 4; ++k)
            {
                result[4*i + j] ^= GFMultplyByte(left[4*i + k], right[4*k + j]);
            }
        }
    }
    return result;
}

AES::AES()
{
    BuildSBox();
    BuildInvSBox();
}

const AES::byte* AES::Cipher(const byte* text, const byte* key, const int& keySize)
{    //    用key给text加密
    for(int i = 0; i < 16; ++i)
    {
        plainText[i] = text[i];
    }

    for(int i = 0; i < keySize; ++i)
    {
        cipherKey[i] = key[i];
    }

    EncryptionProcess();
    return cipherText;
}

const AES::byte* AES::InvCipher(const byte* text, const byte* key, const int& keySize)
{    //    用key给text解密
    for(int i = 0; i < 16; ++i)
    {
        cipherText[i] = text[i];
    }

    for(int i = 0; i < keySize; ++i)
    {
        cipherKey[i] = key[i];
    }

    DecryptionProcess();
    return plainText;
}

#endif /* AES_H_ */



//    main.cpp

#include <string>
#include <fstream>
#include <iostream>
#include "AES.h"

using namespace std;

int main(int argc, char* argv[])
{

    const string USAGE = "Usage:    AES [-E | -D] destinationfile sourcefile keyfile ";

    if(argc != 5)
    {
        cout << USAGE << endl;
        return 1;
    }
    ifstream is(argv[3], ios::in | ios::binary);
    if(!is)
    {
        cerr << "InputFileNotFoundException" << endl;
        return 2;
    }

    ifstream ks(argv[4], ios::in | ios::binary);
    if(!ks)
    {
        cerr << "KeyFileNotFoundException" << endl;
        return 2;
    }

    AES aes;
    const unsigned char *key = new unsigned char[16];

    ks.read((char*)key, 16);

    ofstream os(argv[2], ios::out | ios::binary);


    if(strcmp(argv[1], "-E") == 0 || strcmp(argv[1], "-e") == 0)
    {
        const unsigned char* cipherText;
        const unsigned char* plainText = new unsigned char[16];
        while(is.read((char*)plainText, 16))
        {
            cipherText = aes.Cipher(plainText, key, 16);
            os.write((const char*)cipherText, 16);
        }   
    }

    if(strcmp(argv[1], "-D") == 0 || strcmp(argv[1], "-d") == 0)
    {
        const unsigned char* plainText;
        const unsigned char* cipherText = new unsigned char[16];
        while(is.read((char *)cipherText, 16))
        {
            plainText = aes.InvCipher(cipherText, key, 16);
            os.write((const char*)plainText, 16);
        }   
        delete[] cipherText;
    }

    delete[] key;


    is.close();
    ks.close();
    os.close();

    return 0;
}